Two sets of studies are proposed to investigate the hypothesis that age- related impairments in reasoning and spatial abilities are attributable to a decrease with age in certain aspects of working memory. One set of studies will attempt to identify which aspects of working memory are most influenced by increased age, and to determine the relationship between measures of memory obtained during the processing of on-going cognitive tasks and from tasks deliberately designed to assess memory functioning. the second set of studies will focus on the interrelations of age, working memory, and performance in reasoning and spatial tasks of cognitive functioning. A primary goal of both sets of studies is to specify how age-related limitations of working memory might contribute to lower levels of performance in prototypical cognitive tasks. Ultimately it is hoped that this research will indicate the specific mechanisms by which increased age, and potentially a variety of health-related conditions, influence an individuals's level of cognitive functioning.